1、b=S×2÷h-a=30×2÷4-6=9
2、如果b=5/3a的话b=5/18 h=S×2÷(a+b)=50×2÷(6+5/18)=15.93
如果b=5a/3的话b=10 h=S×2÷(a+b)=50×2÷(6+10)=6.25